A novel graphite-polyurethane composite electrode modified with thiol-organofunctionalized silica for the determination of copper ions in ethanol fuel |
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Authors: | Ivana Cesarino |
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Affiliation: | Departamento de Química e Física Molecular, Instituto de Química de São Carlos, Av. Trabalhador São-carlense, 400, Centro, São Carlos, São Paulo, CEP 13566-590, Brazil |
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Abstract: | A graphite-polyurethane composite modified with 2-benzothiazolethiol organofunctionalized silica was evaluated as an alternative electrode in the determination of Cu2+ ions in ethanol fuel samples, on the basis of a differential pulse anodic stripping voltammetry procedure. This metal can be quantified by mixing ethanol fuel with 0.10 mol L−1 KNO3 aqueous solution and subsequent voltammetric measurement after the accumulation step. A maximum limit of 70% (v/v) ethanol in potassium nitrate aqueous solution was obtained for voltammetric measurements without loss of sensitivity for metal species. Factors affecting the pre-concentration and stripping steps were investigated and optimum conditions were employed to develop the analytical procedure. Using 20 min of accumulation time, the linear range of 0.1-1.2 μmol L−1 was obtained with the limit of detection of 3.9 × 10−8 mol L−1. The developed electrode was successfully applied to determine Cu2+ in commercial ethanol fuel samples. The proposed method was compared with a traditional analytical technique, the flame atomic absorption spectrometry, and no significant differences between the results obtained by both methods were observed according to statistical evaluation. |
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Keywords: | Graphite-polyurethane composite electrode Organofunctionalized silica Ethanol fuel Copper ions |
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